rotary kiln maintenance
The continuity of operation of a lime sludge kiln requires strict maintenance control. The rotary kiln is among the largest type of moving machines made and is subjected to extreme temperatures, power failures, atmospheric conditions, varying loads, and other operating conditions which affect its wear and alignment. It should be erected under the supervision of an experienced erecting engineer.
Even though great care has been taken in the design and the construction of the concrete piers, in some cases settling or tipping of the foundation can occur, throwing the carrying mechanisms, bases, and rollers out of alignment. If this condition is not corrected, it will lead to continual trouble with the kiln shell and the riding rings and rollers. It is advisable when making the original installation of the kiln to establish bench marks away from the kiln foundation. The kiln alignment should then be checked from the bench marks within six months after initial installation, and annually thereafter.
The thrust rollers are designed to carry the full downhill thrust of the kiln, with the riding ring and roller faces lined up for full bearing across the width. Carrying rollers should be set parallel to the axis of the kiln or cut slightly to avoid excessive downhill thrust, which might be detrimental to the thrust roller.
In aligning the kiln by adjusting or cutting the rollers, it is necessary to cut all rollers equally rather than taking all of the cut on one set of rollers. If only one set of rollers is cut to move the kiln in a given direction, and another set of rollers cut to move the kiln in the opposite direction, such action, if continued, would cause various sets of mechanism rollers to work against each other. If this action is carried to extremes, misalignment could occur between any one set of rollers and the corresponding riding ring, resulting in unequal and aggravated wear between the riding ring and roller surfaces. Operators should be discouraged from adjusting only the most easily accessible rollers, which would be on the discharge end mechanisms. A record of all roller adjustments should be kept as an aid to maintaining proper alignment.
When a kiln with a hot charge is stopped for any reason, such as a power failure, it is imperative to keep the kiln rotating with the auxiliary drive. Failure to do so may result in a warped or distorted kiln shell. It is difficult to return a warped shell to its original condition, and operating a kiln with a bowed or warped condition will place an excessive load on various mechanism piers. This is particularly troublesome in multiple support kilns.
Sometimes a warped kiln can be returned to somewhat its original alignment by carefully re-heating the kiln on the side opposite from the warp to draw it back in line. Even at best, though, constant attention must then be given to the carrying mechanisms to provide an alignment which will not cause additional damage or excessive wear.
Sometimes the only way in which to correct a warped or bowed condition or misaligned shell is to cut out a portion of the shell, realign the ridng rings and carrying rollers, and weld the shell section back in. This might result in a slightly disjointed shell, but the items of major importance, namely the riding rings and rollers, are then realigned.
Some kilns are installed without auxiliary drives. This is false economy, since the small additional cost of the auxiliary drive in the initial installation provides good insurance against much more serious difficulties.
The main gear, usually a spur gear, is made in halves with full machined teeth to permit reversing of the gear to obtain a double life. This gear is bolted to a gear flange which is welded to the kiln shell. The driving pinion is mounted on a jackshaft which is coupled to the low speed shaft of an enclosed gear reducer. The gear reducer and jackshaft assembly is fixed to the foundation on the same slope as the kiln, and is provided with adjusting bolts and lugs on the base plate to provide for alignment of the drive. The driving motor is usually connected to the high speed shaft of the gear reducer through a multiple V-belt drive. The motor is also mounted on the same slope as the kiln. Ball bearing motors should always be used, since oil will run out of the bearings on a sleeve bearing motor.
The main gear and pinion should be maintained in proper mesh. Improper meshing of the teeth results in a jerky or vibrating motion of the kiln. Too small a clearance will cause bottoming of the main gear on the base of the pinion teeth. Proper adjustment of the carrying rollers to compensate for the wear on the tires and rollers should prevent this condition.
If a minimum adverse clearance is allowed to continue with a resulting scoring of gear teeth and peening of pinion teeth, it will be necessary to reverse the gear and pinion before such action is normally necessary and then reset the drive accordingly.
Large, slow moving equipment such as rotary kilns will have a low natural frequency of vibration which in some cases could coincide with a kiln speed. Were this to occur, there would be a pronounced vibration of the kiln on the supporting rollers, and knocking and pounding in the main gear and the gear reducer. If such a condition were allowed to continue, the foundations and the kiln could be severely damaged.
The design of the kiln installation insures a natural frequency of vibration well out of the range of recommended operating speeds. Consequently, the kiln speed should never be changed without first investigating the effect which the increased speed might have on the vibrational characteristics of the kiln.
Confirm the original centerline of carrying mechanism bases. To do this, establish an offset centerline, preferably with piano wire, along the side of the kiln from the first to the last support where visibility is unobstructed, as shown in Figure 1. This offset centerline should be equidistant from the centerline marks on the carrying mechanism bases at the two extreme supports of the kiln. By tramming from this offset centerline, determine if the centerline marks on the carrying mechanism bases are all in line.
If the intermediate piers are not in line, determine whether they or the end piers have settled before proceeding with the alignment work. Some changes may be required in order to bring either the bases or piers into line, depending on whether or not the settling has reached its final stages. If no further settling is anticipated, or in cases where no settling has taken place, the offset centerline should be permanently located by setting lead or brass markers into the piers or floor. The true centerline should be clearly marked on each carrying mechanism base by tramming from the offset centerline.
Check the setting of the kiln shell in relation to the true centerline of the bases. This can be done by stringing a cord with a plumb bob attached to each end over the top of the shell as near the riding rings as possible. In cases where there are irregularities in the shell, the cord should be strung over the wearing faces of the riding rings. This cord must be long enough to permit the plumb bobs to hang free beneath the kiln, as shown in Figure 1. The midpoint of the distance between these plumb bobs is the center of the kiln shell at that position. Mark this point on the bases and proceed with the same operation at the next support. Rotate the shell 90 degrees and repeat the markings at each support. The mean of the four marks at each quarter point through a complete revolution will then indicate the path from support to support of the true centerline of the kiln shell.
If condition (2) applies, the carrying rollers must be adjusted so that the true centerline of the kiln shell is made to coincide with the true centerline of the bases. The carrying rollers must be kept parallel to the centerline of the kiln shell and carrying mechanism bases, as shown in Figure 1. In making these adjustments care must be taken to maintain the proper clearance at the feed end and discharge end air seals and at the main drive gear and pinion.
This check should be made when the kiln is shut down and at a time when the shell is not distorted by either radiant heat from adjacent kilns or the sun. Tape the circumference of each riding ring so the distance from the outside diameter of the riding ring to the center of the kiln can be determined for each ring. Set up a transit or level on top of the kiln over the feed end riding ring. Adjust transit so the line of sight is parallel to centerline of the kiln at the feed end and discharge end riding rings. Check the distance from the riding ring to line of sight for each intermediate ring, repeating this check at quarter points around the circumference. Knowing the radius of each riding ring, the average misalignment at each mechanism can now be determined. Correct this misalignment by making the necessary adjustments to the carrying rollers. The slope of the kiln can be checked with the transit at this time.
With the kiln now in correct vertical alignment, a simple gauge can be constructed to check vertical alignment at each mechanism without having to shut down the kiln and go through the elaborate measurements outlined above. This consists of a gauge pin or tram just long enough to reach from the mark of the true centerline on the carrying mechanism frame to kiln shell. A pin should be made for each mechanism frame. Gauging the distance between the frames and the shell will indicate the extent of wear on the rollers and riding rings. The carrying rollers can then be moved in to return the kiln to its original elevation.
Since the shell may not be perfectly round at the planes where the measurements are taken, reference points should be established on the shell so that the vertical distances between the mechanism bases and the shell will always be gauged at the same points on the circumference of the shell. Reference points can be made by welding four -in. nuts to the shell in each plane where measurements are to be taken. These nuts should be spaced 90 degrees apart. A bolt can then be turned into each nut to a point where the head of the bolt will just touch the gauge pin. The bolt is then welded to the nut. Four of these bolts are used at each mechanism to provide an average reading.
The floating type riding rings should not wobble as the kiln rotates, since it is impossible to obtain full contact between the carrying rollers and riding ring under such conditions. Figure 2 shows a method for determining the amount of runout in a ring.
Two pointers are constructed of angle iron and placed as shown. By using two pointers the effect of any kiln float is eliminated. These pointers should be mounted on the kiln pier away from the carrying mechanism and should extend to the centerline of the kiln. The edge of each pointer should be approximately one inch from the machined outer edge of the riding ring.
Measurements are taken from reference marks on the pointers to the machined sides of the riding ring. A set of readings taken at 16 equally spaced points around the circumference of the ring will indicate the location and magnitude of maximum runout. If the runout at any location exceeds it must be corrected by relocating the retaining bands and riding rings.
When rollers are set parallel to the centerline of the kiln, the roller shafts should bear against the downhill bearing caps. This can be checked by tapping the bearing caps with a hammer. The loaded caps will emit a solid sound.
Check each downhill bearing cap to make certain there is no excessive downhill thrust on any cap. This is done by cutting the roller to just relieve the pressure of the roller shaft against the cap. Note how much the adjusting screw was turned. Then return the roller to a setting which will just produce a light roller shaft force against the downhill bearing cap. After all the rollers are adjusted the kiln will bear against the lower thrust roller. Care must be taken to avoid excessive thrust roller loading.
Sometimes, when starting up a new kiln with the carrying rollers set parallel to the axis of the kiln, the carrying rollers and riding rings will not make 100% contact throughout the complete revolution of the kiln. In such cases it is better to let the rolling surfaces wear in to obtain full contact rather than to adjust the rollers to obtain full contact immediately.
The thrust mechanisms on modern kilns are designed to carry the full thrust of the kiln. On many older kilns, however, it is necessary to carry much of the thrust by adjusting the carrying rollers, since the thrust mechanisms were not designed to take the full thrust load. To float the shell of such a kiln, thus reducing or even eliminatingcompletely the thrust on the downhill thrust roller, the carrying rollers are set at an angle as shown in Figure 3. The illustrations exaggerate the amount of adjustment to show the principle involved more clearly. Any such adjustments must be performed carefully with each roller to avoid excessive pressure with resultant wear from developing on any one roller.
The main gear is equipped with adjusting screws to facilitate centering of the gear on the shell.
This gear must run true. Several points around the circumference of the gear should be checked with a feeler gauge for uniform contact across the full face of the teeth. Flange bolts should be inspected periodically to be sure they are tight at all times. A tight fit can be achieved by pulling each bolt up tightly, then heating the bolt to about 350 F and advancing the nut an additional 20 degrees.
The pinion and gear must mesh properly, as shown in Figure 5. Pitch lines are scribed on both sides of the gear and pinion at the factory. The pinion should be set so the pitch lines on the gear and pinion are 1/16 in. apart when the shell is cold. When the shell is hot the pitch lines should be from 0 to 1/16 in. apart. In no case should the pitch lines overlap, since this would cause excessive wear and overloading of the pinionshaft and bearings.
The mesh of the gear and pinion should be checked at regular intervals. Any wear or adjustment on the carrying rollers will change the mesh. If the pinion is meshing too deeply, the kiln should be raised to its original position by moving the carrying rollers in toward the centerline of the kiln. It should not be necessary to back the drive out to obtain the correct mesh. While the drive is equipped with adjusting screws, these are mainly for use in the initial alignment of the drive. Sometimes it becomes necessary to back the drive away from the kiln to relieve a serious condition which, if permitted to continue, would result in damage to the gear and pinion. This must be considered only a temporary expedient, and the drive should be returned to its correct location immediately upon returning the shell to its true centerline in the recommended manner.
Sometimes it becomes necessary to reface riding rings or rollers. A grinding rig, shown in Figure 6, can be constructed on the job and used to reface the riding rings while the kiln is in operation. The coil springs and adjusting bolts serve as a stop so that the high spots on the ring will be ground off first. In operating this refacing tool, a reference mark should be established on the side of the riding ring being ground, and the adjusting screw on the tool turned one revolution per revolution of the kiln to assure even grinding across the face of the ring. Any circumferential ridges on the ring must be ground off first.
If it is not feasible to operate the tool throughout a full 24-hour period, it is a simple matter to lower the grinding table on the adjusting bolts, thereby removing the carborundum blocks from contact with the riding ring. This tool can also be adapted for refacing the carrying roller by tipping the rig up on its side and setting it against the face of the roller. This can be more easily accomplished on the outer side of the carrying mechanism due to space limitations, especially at the thrust mechanism. These rollers can also be refaced by using a lathe and cutting tool arrangement, or it may be more expedient and economical to put the kiln on cribbing and reface the rollers in the machine shop. In either case, whether the ring and roller are to wear in over a period of time or whether they are to be refaced, it is essential to watch the following:
Use high grade lubricant with specifications shown in Figure 7. After a new kiln has been in service for one month, drain oil and clean reservoir. Refill with new oil. Thereafter change oil every six months.
Use high grade lubricant with specifications shown in Figure 8. The oil level should be checked at frequent intervals and maintained at the proper level. When starting a new kiln the level should be checked daily. The oil should be changed after the first month of operation and at six-month intervals thereafter.
Floating type riding rings should be lubricated between riding rings and filler bars with a graphited grease. Initially, apply lubricant to the inner surface of the riding ring at all spaces between filler bars. Subsequent applications of lubricant need be made only at four evenly spaced points around the circumference of the ring. The lubricant can be most easily applied with a hand gun with extended nozzle.
rotary kiln refractory: preventative care
The refractory in a direct-fired rotary kiln is a crucial component, serving to both protect the shell of the drum and combustion chamber from the high interior temperatures, and to minimize heat loss. As a result, protecting refractory is not only critical to promoting optimal efficiency, but also to maintaining and prolonging the life of a rotary kiln.
Refractory failure has the potential to cause catastrophic consequences if left unaddressed. Significant downtime, extensive maintenance or even total kiln replacement, as well as lost production, can all result from refractory that has been allowed to degrade.
A well-installed, high-quality refractory can have a lifespan of many years. There are several factors, however, that have the potential to cut refractory life short if not properly monitored and managed the most common of which, are summarized below.
Each time the rotary kiln is heated, the refractory expands with the drum. As the kiln cools down, the refractory retracts. If a kiln is constantly being heated up and shut down, the refractory can easily become stressed, causing cracks. Similarly, cracks can also occur from heating or cooling the kiln too quickly, which also stresses the refractory.
Chlorides can aggressively attack refractory, causing excessive wear because of their corrosive nature. When these chemicals are identified up front, refractory can be designed to handle such aggressive corrosion as best as possible. However, if not prepared for in the initial design, chlorides or other corrosive materials can quickly degrade refractory.
Like corrosion, refractory can be designed to combat an abrasive material, but if not prepared for in the initial design, can have devastating effects. For example, when compared to castable, brick refractory wears less in the presence of an abrasive material and may be the refractory of choice when working with an especially abrasive material.
Signs of refractory damage or failure can be difficult to recognize. And since damage can accelerate quickly, regular monitoring is critical to catching problems early. Any potential signs of damage should be addressed immediately to avoid escalation of an issue to a more severe situation.
Refractory should be regularly inspected as part of the overall preventative maintenance program. When permissible, operators or a customer service engineer from the original equipment manufacturer should inspect the refractory from the inside of the drum to check for the start of any potential cracks or wear while the unit is shut down.
Castable refractory can exhibit hairline cracks over time. If anchors are not properly installed, these cracks can get bigger and allow portions of refractory to fall out. Similarly, these hairline cracks can become bigger, trapping material and creating hot spots.
While not a guaranteed method of detection, refractory problems can also be detected through regular monitoring of the drum shell temperature. This can be done by picking a spot on the rotary kiln shell and holding a temperature gun in place. As the rotary kiln rotates, that spot should be the same temperature for the entire circumference of the shell. For example, a reading of 400, 400, 700, 400 reveals a hotspot on the shell, indicating a failure in refractory. Left unnoticed, this could lead to severe damage to the rotary kiln shell.
In addition to circumference temperature being the same in a given location, the kiln should also exhibit a gradual shift in temperature from one end of the kiln to the other, rather than a drastic or sudden change.
Refractory failure can have disastrous results. Even a small crack can allow heat to reach the rotary kiln shell. It is important to routinely check the exterior temperature of the rotary kiln shell, ensuring that the temperature is consistent for the entire circumference of the drum.
Regularly monitoring and maintaining the refractory in a direct-fired rotary kiln is essential in achieving maximum efficiency and prolonging the overall life of the rotary kiln. Various factors can cause failure and early detection is critical to avoiding excessive downtime, maintenance or replacement costs, and lost production.
FEECO is a leading manufacturer of custom rotary kilns. We also provide a comprehensive range of parts and service support, including annual inspections, to help keep rotary kilns running optimally. For more information on preventative care for rotary kilns, contact us today!
FEECO is a leading manufacturer of highly engineered, custom rotary kilns for processing solids. Our high temperature kilns have earned a reputation for their durability, efficiency, and longevity. We offer both direct- and indirect-fired units.
Rotary kilns work by processing material in a rotating drum at high temperatures for a specified retention time to cause a physical change or chemical reaction in the material being processed. The kiln is set at a slight slope to assist in moving material through the drum.
Direct-fired kilns utilize direct contact between the material and process gas to efficiently process the material. Combustion can occur in a combustion chamber to avoid direct flame radiation, or the flame can be directed down the length of the kiln.
All FEECO equipment and process systems can be outfitted with the latest in automation controls from Rockwell Automation. The unique combination of proprietary Rockwell Automation controls and software, combined with our extensive experience in process design and enhancements with hundreds of materials provides an unparalleled experience for customers seeking innovative process solutions and equipment.
Indirect-fired kilns are used for various processing applications, such as when processing must occur in an inert environment, when working with finely divided solids, or when the processing environment must be tightly controlled.
Calcination refers to the process of heating a material to a temperature that will cause chemical dissociation (chemical separation). This process is used frequently in the creation of inorganic materials, for example, the dissociation of calcium carbonate to create calcium oxide and carbon dioxide.
Thermal desorption is also a separation process. This process uses heat to drive off a volatile component, such as a pesticide, from an inorganic mineral, such as sand. The component is vaporized at the increased temperature, causing a separation without combustion. In some cases, an indirect rotary kiln would be best for this application, because the volatile chemicals may be combustible. The indirect kiln will supply the heat for desorption, without the material coming into direct contact with the flame.
Organic combustion refers to the treatment of organic wastes with the intent of reducing mass and volume. Organic waste is treated in the kiln, leaving behind an ash with considerably less mass and volume. This allows for more efficient and effective deposit of waste materials into landfills.
Sintering is the process of heating a raw material to the point just before melting. This increases the strength of the material, and is commonly used in the proppant industry, where sand or ceramic materials are made stronger.
Heat setting involves bonding a heat resistant core mineral with another, less heat resistant coating material. Unlike an unheated coating process, here, a rotary kiln heats the coating material to just below liquefaction point, allowing it to coat the heat resistant core more evenly and more securely. This process is commonly seen in the manufacture of roofing granules, where a mineral such as granite is coated with a colored pigment, producing a product that is both durable and aesthetically pleasing.
Reduction roasting is the removal of oxygen from a component of an ore usually by using carbon monoxide (CO). The CO is typically supplied by mixing a carbonaceous material such as coal or coke with the ore or by feeding it separately. Examples are the reduction roasting of a hematite containing material to produce magnetite that can be magnetically separated. In the Waelz process, zinc oxide in steel mill wastes is reduced to metallic zinc and volatilized for recovery in the off-gas system.
Thermal Desorption for Spent CatalystsRotary Kiln3D Indirect Kiln for Activated CarbonPyrolysis Kiln Seal3D FEECO Pyrolysis KilnPyrolysis KilnWorn Rotary Kiln RefractoryKiln Alignment SoftwareBatch Rotary Kiln TestingProcessing Challenges When Working with Rotary KilnsFEECO Batch Kiln BrochureIndustry Focus COVID-19 Demands Medical Waste Incineration CapacityIndirect Fired Rotary Kiln ReplacementRotary Kiln IncineratorsResource of the Week: Thermal Testing with Kilns3D Model of a FEECO Carbon Activation KilnRotary Kiln Testing ThumbnailRotary Kiln TestingIndirect Batch Rotary Kiln Testing, Batch Calciner Testing, Thermal Process DevelopmentKnowing When its Time to Replace Your Rotary Drum Seal, Leaf SealRotary Drum Drive ComponentsRotary Drum BreechingReplacement Rotary Drum BearingsBoomin Catalyst Market Drives Demand for Rotary Kiln Repair Services, Rotary KilnsReplacement Dryer (Drier) and Kiln BurnersCombustion ChambersReplacement Rotary Drum ShellRotary Drum Laser Alignment Process, Rotary Drum AlignmentWhy Post Maintenance Alignment is Critical to Rotary DrumsCauses of Tire (Tyre) and Trunnion Wear, Rotary Drum TireFEECO Tire (Tyre) Grinding Machine, Tire and Trunnion Grinding in ProgressRotary Drum Tire (Tyre) Wear Pattern from Excessive Wheel Skewing, Rotary Drum Tire in Need of Tire GrindingRotary Drum Tire (Tyre) Wear Pattern from Poor Housekeeping Practices, Rotary Drum Tire in Need of Tire GrindingRotary Drum Tire (Tyre) Wear Pattern from Misalignment, Rotary Drum Tire in Need of Tire GrindingRotary Drum Tire (Tyre) Wear Pattern from Using Improper Tire Lubricant, Rotary Drum Tire in Need of Tire GrindingTire (Tyre) and Trunnion Wheel GrindingTire (Tyre) and Trunnion GrindingIndirect Rotary Kiln (Calciner) for Plastics PyrolysisPlastic to Fuel Conversion via Pyrolysis Replacement Rotary Drum PartsRotary Drum Thrust RollersRotary Drum Trunnion Wheels (Rollers)Rotary Drum Riding Ring (Tire/Tyre)Resource of the Week: Girth Gears PageRotary Kiln System Optimization, Rotary Kiln Process AuditSpring-Mounted Replacement Rotary Drum Girth GearRotary Kiln Gains Traction as E-Waste Crisis Looms, Metal Recovery from E-WasteIndirect Batch Rotary Kiln Testing, Batch Calciner Testing, Thermal Process Development, Metal RecoveryDirect-Fired Rotary KilnRotary Kiln Chain and Sprocket Drive AssemblyRotary Kiln Gear and Pinion Drive AssemblyRotary Kiln Friction Drive AssemblyRotary Kiln Direct Drive AssemblyRotary Kiln Trunnion BaseRotary kiln end dam for increasing loading, retention time, and bed depthResource of the Week: Rotary Kiln Customization Slideshare PresentationKaolin Clay CalcinationLithium-ion Battery Recycling OpportunitiesRotary Kilns in Expanded Clay Aggregate ProductionBatch Kiln for Testing Expanded Clay AggregatesRotary Kiln Refractory Failure Illustration, Rotary Kiln Shell Hot SpotRotary Kiln Refractory InspectionDirect-Fired Rotary Kiln for SpodumeneCalciner (Indirect Kiln) for Lithium Recovery from SpodumeneRotary Kiln Complete SystemFEECO Batch Kiln for Testing CalcinationRotary Drum Drive BaseRotary Kilns for Advanced Thermal Processing in SustainabilityResource of the Week: Project Profile on a Rotary Kiln (Calciner) Resource Recovery SystemResource of the Week: Tire Grinding BrochureResource of the Week: Slideshare Presentation on Rotary Kiln Sizing and DesignResource of the Week: Unitized Drive Base BrochureDiagram Showing a Rotary Kiln with Co-current AirflowDiagram Showing a Rotary Kiln with Counter Current AirflowDiagram Showing Co-current Airflow
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The advantages to a FEECO rotary kiln are that it is built to the highest quality standards and is backed by over 60 years of process design experience. The FEECO Innovation Center offers batch and pilot scale kilns that can simulate conditions in continuous commercial rotary kilns, allowing our customers to test small samples of material under various process conditions, as well as part of a continuous process. With options in both co-current and counter-current flow, and direct or indirect configurations, the FEECO test kilns offer a variety of options to suit your thermal testing needs. We also offer support equipment such as a combustion chamber, afterburner, baghouse, and wet scrubber for testing.
how much is a kiln / rotary kiln price
As the construction of modern cities, many urban houses are tearing down. Cement has become the most frequently used material and gains more and more market demands; Normally, processing way is calcinating and the needed equipment is rotary kiln. Customers always pay more attention to the price during purchase.
After a national-wide interview and investigation, the general price of a rotary kiln is between 3000$ to 15000$. A small rotary kilns price is about 4000$ while a large rotary kiln line with other equipment can be 15000$. This text will focus on analyzing the price factor of the rotary kiln.
As the commodity price keeps rising, the higher and higher rotary kiln price is a necessary trend. Under this general trend, many manufacturing factories have to raise their market competitive power by any method to increase overall sales volume. Some are healthy competition like gaining customers fever by raising product quality and grab customers accept by raising the band image. The others, on the contrary, achieve the goal of reducing the price by cutting costs. It is unhealthy for market development, which will be weed out sooner or later.
The production cost closely connects to the sales price. High-cost equipment always with excellent configuration and better performance, so the price is higher. On the contrary, the price overtly decreases. To raise the equipments cost performance, we should keep decreasing costs while increasing product performance. Then the equipment will be popular.
Rotary kilns quality is a key factor in influencing the price. Normally, better quality brings a higher price. Because high cost means larger input. But it will be more stable in using the process with high efficiency and high yield. On the contrary, some unqualified rotary kiln, although it is cheap, will make errors while running and has larger energy consumption and big cost and will bring the huge economic cost to enterprises.
Only products with good quality will bring customers reassurance and live a long service life. This kind of equipment can take positive economic income. AGICO group checks product quality at all levels, so our rotary kilns quality is insured and our price is reasonable. Thats why our products have a high sales volume.
For now, there are many rotary kiln type on market for sale. Different types mean different technological parameters with divided processing ability. Different parameters also represent different price.
In so many rotary kiln sellers in Henan province, some are direct selling factories and others are middleman factories. Large scales companies exist, while small scales companies also exist. Every company offers a different price, costumers can choose proper factories by analyzing their technological strength and after-sale service.
Besides the above-fixed factors, there are also some factors will influence the overall price of rotary kiln such as customers demands, market, the relationship between supply and demand and economic mode. Only after overall analysis and consideration, you can make your more accurate choose.
production of ferrochrome from low-grade ores - sciencedirect
A method for production of charge grade ferrochrome from concentrate is described. The Outokumpu process of pelletizing and hardening in a shaft furnace of chromite concentrates and fines is presented. The preheating of pellets with additives in a rotary kiln by furnace gas and smelting in a totally closed electric furnace with low energy consumption, putting special emphasis on environmental consideration, is described and operational data are given.